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자동 8자 위빙 장치를 장착한 알곤 용접토치 및 제어장치의 개발
사의환(Yui-hwan Sa),정성용(Sung-Yong Jung),차형우(Hyeong-Woo Cha) 대한전자공학회 2016 대한전자공학회 학술대회 Vol.2016 No.6
An argon welding torch mounted automatic 8-style weaving device and its the control equipment was development. The welding torch consists of automatic wire supply, 8-style weaving device, conventional torch and control switches. The control system using Arduino can control initial setting up, wire supply, 8-style weaving, and start/stop welding. The fixtures of 8-style weaving device, wire supply, and its control system were also designed and developed.
제3-고조파를 이용한 저항과 용량형 센서 인터페이스 회로 설계
사의환(Yui-Hwan Sa),손표훈(Pyo-Hoon Son),김기홍(Ki-Hong Kim),김희석(Hi-Seok Kim),차형우(Hyeong-Woo Cha) 대한전자공학회 2016 대한전자공학회 학술대회 Vol.2016 No.11
A novel resistive and capacitive interface circuit using third harmonic frequency was designed. The interface consists of fixed and variable pulse-wave oscillators, two band-pass filters with third harmonic center frequency of the two oscillators, a multiplier, and a low-pass filter(LPF). The band-pass filter outs three times capacitive(resistive) -difference frequency of the fixed and variable capacitor(resistor). The difference frequency of the multiplier was filtered by LPF and than final frequency of the LPF was proportioned to the three time of capacitive (resistive)-difference. The experimentation results show that the proposed interface has resolution of 1.59Hz/fF and nonlinearity error of 1.86%.
CMOS 트랜지스터로 구성된 온도 보상된 LDO Regulator 설계
김진수(Jin-Su Kim),사의환(Yui-Hwan Sa),이원호(Won-Ho Lee),조민형(Min-Hyeong Cho),차형우(Hyeong-Woo Cha),김희석(Hi-Seok Kim) 대한전자공학회 2015 대한전자공학회 학술대회 Vol.2015 No.6
A new temperature compensation LDO (low drop out) regulator configured CMOS transistors was designed. The proposed regulator circuit is consist of temperature compensation band gap reference and LDO. The simulation results that the proposed regulator has output voltage of 1.5V from 2.1V to 5.5V of supply voltage and temperature coefficient of 250ppm/℃ form ~ 20℃ to 140℃. The designed regulator for circuit simulation was used as the Magna/Hynix 0.35㎛ process and supply voltage was 5V.
자율주행차량의 객체 검출을 위한 카메라-라이다 센서 시각 동기화 방안 연구
최경수(Kyoung Soo Choi),사의환(Yui Hwan Sa),김성진(Sung Jin Kim),강대수(Dae Soo Kang),이정욱(Jung Uck Lee) 한국산학기술학회 2023 한국산학기술학회논문지 Vol.24 No.10
최근 자율주행차량에 관한 다양한 연구가 진행되고 있으며 특히, 인공지능 학습을 위한 GPU와 주변 하드웨어 성능 향상으로 주변 객체 검출을 통해 자율주행차량을 지원하고 있다. 객체 검출을 위한 대표적인 센서는 카메라, 라이다, 레이더가 있으며, 단일 센서의 인지 능력보다 다종 센서의 융합을 통해 검출 정확도를 높이는 것이 높은 신뢰성을 요구하는 자동차 분야에서 선호하는 방식이다. 따라서, 본 논문에서는 카메라와 라이다 센서의 융합 방식을 채택했다. 인공지능 학습 성능을 높이기 위한 요인 중 이기종 센서 간 캘리브레이션과 정밀한 시각 동기화 방식을 통한 객체 검출 성능 검증을 수행했다. 캘리브레이션 방식은 크게 체커보드 기반, 비 목표물 기반, 딥러닝 기반으로 구성되어 있고, 그 중 Zhang’s method 기반 캘리브레이션을 진행하였으며 회전 오차: 0.80°, 이동 오차: 0.02m, 재투영 오차: 7.63 픽셀의 결과를 도출했다. 다종 센서의 시각 동기화는 트리거 신호의 주기와 근적외선 카메라를 통해 확인하였고, 차량의 속도별 투영 이미지를 이용하여 정성적인 성능을 검증했다. Various studies on autonomous vehicles have been conducted. In particular, autonomous vehicles are supported by detecting the surrounding objects by improving the GPU and surrounding H/W performance for artificial intelligence (AI) learning. Representative sensors for object detection include cameras, lidar, and radar, and it is preferred in the automotive field, requiring high reliability to increase detection accuracy through the fusion of multiple sensors rather than the cognitive ability of a single sensor. Therefore, this paper used the convergence method of camera and lidar sensors. Object detection performance was verified through calibration between heterogeneous sensors and precise time synchronization to improve the AI learning performance. The calibration method is largely checkerboard-based, non-target-based, and deep learning-based, of which checkerboard-based calibration was conducted. The following results were derived: rotation error, 0.80°; translation error, 0.02m; reproduction error, 7.63 pixels. Time synchronization of various sensors was confirmed from the period of the trigger signal and the near-infrared camera, and qualitative performance was verified using projection images by the vehicle speed.
FlexRay 트랜시버 시스템의 Bus Driver(BD) 회로 제작 및 검증
조민형(Min-Hyeong Cho),이원호(Won-ho Lee),사의환(Yui-Hwan Sa),김진수,김희석(Hi-Seok Kim),차형우(Hyeong-Woo cha) 대한전자공학회 2015 대한전자공학회 학술대회 Vol.2015 No.11
Bus driver circuit of FlexRay transceiver system was fabricated and tested. the Bus driver circuit configured transmitter circuit and receiver circuit. In the verified circuit transmitter circuit, data0, data1, idle, and idle_lp are control signals decoded by a one-hot decoder and fed into the bus driver. Furthermore, a three comparator scheme is used to carry out bit slicing and state recognition at the receiver circuit end. The verified circuit was used as the Magna/Hynix 0.18㎛ process and supply voltage was 3.3V. As a result of chip test, It was confirmed the output waveform change according to the control signal. BD is normal operation to 500㎑. But, up to 500㎑, the output waveform is occurred distorted phenomenon.
이원호(Won-ho Lee),조민형(Min-Hyeong Cho),사의환(Yui-Hwan Sa),김진수,김희석(Hi-Seok Kim),차형우(Hyeong-Woo Cha) 대한전자공학회 2015 대한전자공학회 학술대회 Vol.2015 No.11
CAN transceiver for communication of car network was designed. Driver circuit consists of UVLO, temperature protect, driver, oscillator, Time out and receiver circuits. It provides CANH, CANL signals for CAN communication"s physical layer standard. Timeout circuit consists of 3bit binary counter using D flip-flop, OR gate and NOT gate. It protects the CAN bus against permanent blocking that TxD is continuously "low". The verified circuit was used as the Magna/Hynix 0.18㎛ process and supply voltage was 3.3V. As a result of chip test, waveform and value is correspond with simulation.